In a modern digital integrated circuit (IC), there are many factors contributing to soft errors in a circuit component, including ionizing radiation (particles and electromagnetic), random thermal and shot noises, and inductive/capacitive crosstalk. For many applications, particles and electromagnetic radiations are the main causes of soft errors due to their intensity and/or proximity to the transistors within the IC.
Particles radiation originates from alpha particle (nucleus having two protons and two neutrons) emission and energetic neutron/proton emission. Alpha particles are frequently detected during the decay process from radioactive packaging materials used in semiconductor packaging. Since packaging materials may be used to encapsulate IC chips for protection and lead connections, alpha particle decay often occur within a few millimeter of the semiconductor in the IC.
Energetic neutrons and protons may be created from high energy electromagnetic radiations impinging on atmospheric particles, thus emitting energetic neutrons and protons. Energetic neutrons that cause soft errors in IC may also come from collisions between neutrons' random motions and thermal agitations of particles surrounding neutrons.
While soft errors typically will not lead to catastrophic break-down of components on an IC chip, they do cause logic errors, and may require the components containing the soft errors to re-compute their stored logic values. For example, a register may store a certain byte value for central-processing units operations. If a soft error occurs within the register, the CPU operations cannot be properly performed unless the correct stored value is somehow retrieved. When dealing with soft errors in IC, an engineer may employ a variety of ways to mitigate, correct, or at least acknowledge soft errors.